Method for operating an adjusting apparatus and means for adjusting a positional device

ABSTRACT

A method and apparatus for operating a positioning device for an adjustable device. The positioning device is mechanically actuated by a bearing connected to a pivotable armature that interacts magnetically with an electromagnet. The electromagnet is energized by current pulses generated by a computer program. The current pulses cause the air gap between the pivotable armature and the electromagnet to vary between open positions where the electromagnet is not magnetized, and a closed position where the electromagnet is magnetized. Several bearings and associated electromagnets may be arranged to operate the positioning device in one or more directions and at different torques and operating speeds for different directions of operation and different positions of adjustment.

This is application is a 371 of PCT/SE95/00613 filed on May 30, 1995.

TECHNICAL FIELD

The present invention relates to a method of operating at least oneadjusting/positioning apparatus for an adjustable device, means ofoperating an adjustable device and an application of the said means.

STATE OF THE ART

The use of rapid pulses to drive a motor shaft through anelectromagnetically vibrated (oscillating) arm mounted on the shaft haslong been known. The shaft may be driven reversibly by an arrangement oftwo electromagnetically vibrated arms (see U.S. Pat. No. 1,860,492 andDE-C-349 678).

The use of a ratchet connected to a solenoid or electromagnet energizedby an alternating current as a stepping drive for a disc device is alsoknown (see U.S. Pat. No. 3,530,346 and CH-C-469 393).

The control of a feeder for handling vibrating material is known fromU.S. Pat. No. 4,554,490. An optimum speed for conveying material so asto improve the feeding efficiency, reduce noise levels and reducemechanical wear and tear on the equipment can be achieved by varyingstrokes and driving frequencies.

A disadvantage of known devices which use pulse-controlledelectromagnets is that they use rapid oscillating pulses, a method whichis not always suitable for operating adjustable devices, in addition towhich the pulse length, frequency and amplitude cannot be varied atdifferent times and at different positions of adjustment.

SUMMARY OF INVENTION

The present invention relates to a method and means of using at leastone tool to operate an adjusting/positioning apparatus for an adjustabledevice, the tool being actuated mechanically by a moving elementinteracting magnetically with an electromagnet.

The electromagnet is energized by current pulses controlled by acomputer program, the moving element actuating the tool operatingadjusting/positioning apparatus in response to the current pulses inorder to operate the adjustable device in accordance with the computerprogram. Several tools may be connected to the adjusting/positioningapparatus separately and/or in series and/or in parallel to operate theadjusting/positioning apparatus in one or the other direction at thespecified torque/operating speed for different directions of operationand/or at different positions of adjustment.

The mutually dependent or independent current pulses for theelectromagnets in question may be of a fixed or variable frequency, andthe moving elements in question may be controlled to assume air gaps ofdifferent sizes with respect to the electromagnet under the control ofthe computer program.

In one embodiment of the invention, the adjusting apparatus consists ofa threaded shaft provided with a fastener, such as a nut, to secure theadjusting apparatus to the adjustable device. The tool for operating theadjustable device may consist of an actuating/ratchet device.

The invention relates particularly to the use of the means of operatingor positioning one or more adjustable devices in a vehicle, preferablyusing a single computer to control all of the magnetizing pulses.

Other special features and characteristics are described in the appendedpatent claims.

The invention is particularly applicable as a small, powerful,slow-acting motor, such as a linear motor, angle motor, stepping motoror suchlike, or as an actuator for operating and adjusting a device,such as turning a shaft, in instances in which solenoids are toofast-acting.

An advantage of the method and means in accordance with the invention,compared with other known adjusting devices, is the wide range ofadjustment facilities, in terms of torque and speed of operation,available for different directions of operation, as well as fordifferent adjustment times and positions. This is due to the computercontrol of the induced magnetizations of the electromagnets, which aredetermined by several parameters, such as current pulse frequency, pulseamplitude and pulse length, and by the nature of the mutual dependencybetween the magnetization pulses.

Another advantage is the simple compact construction as well as thereliability of the means in accordance with the invention, which isintended primarily to replace devices, such as servomotors, which areoften used with adjustable devices, for example, for window regulators,seats and rear view mirrors in vehicles.

The electromagnet with moving element in accordance with the inventiondiffers from conventional electromagnets with two positions, an open,maximized position and a closed (attracted) position. Thus, for example,the invention makes it possible to choose continuously from a maximumoperating speed and the associated minimum torque, to a minimumoperating speed and the associated maximum torque. As a furtheradvantage, the invention makes it possible, when positioning, to operatethe adjustable device at maximum force and low operating speedinitially, then to reduce the force and increase the speed, while usinganother, optional operating speed/force in the other direction.

DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

The invention will be described in detail below with reference to theappended drawings, of which

FIG. 1 is a schematic view of a means of operating an adjustable devicein accordance with the invention;

FIG. 2 is a schematic illustration of an adjusting apparatus driven byseveral electromagnetically operated actuating/ratchet devices;

FIG. 3 is a diagram showing the size of the air gap as a function oftime;

FIG. 4 is a diagram illustrating the relationship between torque andoperating speed at a specified frequency and amplitude.

FIG. 1 shows a moving element 1 made of a magnetic material, whichelement interacts with an electromagnet 2, the winding of which issupplied with an alternating current. In the embodiment shown, themoving element 1 consists of a pivoted armature, the free end of whichcan assume a closed position B when the electromagnet is energized by acurrent, and positions A when the electromagnet is not energized i.e.when no current is flowing in the winding. Positions A are all positionswhich may be assumed by the moving element 1 when the electromagnet isnot energized. The moving element may assume a maximum distance from theelectromagnet, with or without the provision of a stop (not shown),while the moving element 1 may move between positions A and position Bin step with the current pulses supplied to the electromagnet 2. Themoving element 1 and interacting electromagnet 2 may, naturally, be ofanother optional design, for example a push/pull magnet, suitable for aspecific purpose.

Furthermore, the invention may be provided with optional devices (notshown) to pull the moving element 1 into the maximum open position, andto retain it in that position, when the electromagnet 2 is notenergized.

In the example shown in FIG. 1, the other end of the moving element 1mechanically actuates a tool 3 which, in turn, operates an adjustingapparatus 4. The tool 3 may be of an appropriate type, preferably ajournalled ratchet, although all types of tractive/ratchet devices, suchas a strap, or other bearing arrrangements, may, naturally, also beused.

In the embodiment shown in FIG. 1, the adjusting apparatus 4 consists ofa threaded shaft attached to the adjustable device (not shown) by meansof a fastener, such as a nut. The shaft is turned in the directionindicated by the arrow.

FIG. 2 illustrates schematically how moving parts 1a, 1b, 1c and 1d maybe arranged to actuate corresponding tools 3a, 3b, 3c and 3d, to drive(and lock) the shaft 4 in two different directions, the tools 3a and 3bbeing arranged to drive the shaft clockwise and the tools 3c and 3d todrive it counterclockwise.

Other types of adjusting apparatus, such as discs, wheels, drums,plates, rods aligned in various directions, and so on, may, naturally,also be used to position/adjust the shaft in one or more dimensions.

FIG. 3 exemplifies the operation of a shaft 4 by moving parts 1a and 1bin combination, in which, at time t₀, the moving part 1a starts to drivethe shaft 4, through tool 3 (not shown), at a low force (large air gapl₀) and, at time t₁, receives assistance from the moving part 1b todrive the shaft at a higher force (smaller air gap l₁), until the movingparts 1a and 1b reach the closed position B at time t₃.

It will be seen that a device may be operated in an almost unlimitednumber of ways by varying different parameters, such as thecurrent/pulse frequency, pulse amplitude and pul length, the possibledistance between the moving element and the electromagnet, the positionand design of the particular moving element/adjusting apparatus, thenature of the electromagnet and winding, the directions of action, andso on.

According to the invention, the frequency, number and magnitude of thecurrent pulses are determined by the program in a computer (not shown inFIG. 1) connected to the winding of the electromagnet 2. Magnetizationof the various electromagnets i.e. the order in which they areconnected, whether they should be connected in series or parallel orenergized individually, or whether they should be mutually energized bydependent or independent current pulses, is controlled by the computerprogram which, as a result, can provide different operatingcharacteristics for different directions and at different positions ofadjustment, and can determine the torque as a function of the air gap.The magnitude of the operating movement achieved by the tool (3) as themoving element switches from the open position A to the closed(attracted) position B is dependent on the size of the air gap which, inturn, is a function of the time during which the electromagnet is notenergized.

It will be seen from FIG. 4, together with FIG. 3, that if the currentis zero for a longer period (see FIG. 4), the moving, unmagnetized part(1a) will have time to be pulled to have a larger air gap relative tothe electromagnet (2), with the result that the shaft 4 will pivotedthrough a greater distance, at a correspondingly lower torque, inresponse to the next current pulse while, if the current is zero for ashort period (see FIG. 4b), the moving, unmagnetized part (1b) will haveinsufficient time to move any considerable distance from the closed(attracted) position B and the shaft (4) will only pivot through a shortdistance in response to the next current pulse, although at acorrespondingly higher torque. Specifying the length of the currentpulse, at a given frequency and amplitude, affords the option ofoperating the shaft at high force and low operating speed, or in someother manner.

The means of operating devices may be used to advantage toadjust/operate various devices in a vehicle, such as the windowregulators, rear view mirrors, seats, boot lid, doors, (central) locks,sunroof, filler cap, air dampers, and so on, each of which, in additionto operating devices of different kinds, requires a different method ofoperation in terms of force, speed etc.

A single on-board computer may be programmed to control the currentpulses for the various adjustable devices, to ensure optimum adjustmentof the devices. Since programming of the computer to perform the variousoperations is state of the art, it is not dealt with in this descriptionof the invention.

I claim:
 1. A method of operating a positioning apparatus for anadjustable device connected to bearings arranged individually, orconnected to each other in series or in parallel, comprising:connectingeach bearing to a pivotable armature, said pivotable armatureinteracting magnetically with an electromagnet; generating currentpulses in the electromagnet with a computer program; mechanicallyactuating the bearings by selectively magnetizing the electromagnet withthe current pulses to vary the size of the air gap between the pivotablearmature and the electromagnet, thereby alternating the pivotablearmature between open positions where the electromagnet is not energizedand a closed position when the electromagnet is energized, wherein thecurrent pulses control the directions of operation and positions of thepositioning apparatus as well the torque and speed of the bearings. 2.The method according to claim 1, wherein the positioning apparatus isoperated in one direction by at least one bearing and in anotherdirection by at least one bearing.
 3. The method according to claim 4,wherein the current pulses have variations in frequency and amplitude.4. The method according to claim 3, wherein the current pulses areselected from the group consisting of fixed frequency pulses andvariable frequency pulses.
 5. The method according to claim 4, whereinthe torque and operating speed of the bearings actuating the positioningapparatus are controlled by specifying the frequency and amplitude ofthe current pulses controlling the air gap.
 6. A positioning apparatusfor operating an adjustable device, comprising:a positioning device; aplurality of bearings arranged for actuating the positioning device; apivotable armature connected to each bearing; an electromagnetmagnetically connected to each pivotable armature; and a computeradapted to generate current pulses in the electromagnet and therebycontrol the position and direction of operation of the positioningdevice, wherein the current pulses cause said pivotable armature toalternate between open non-magnetized positions with air gaps of varyingsizes with respect to the electromagnet, and a closed position, to varythe torque and speed of the respective bearing.
 7. The apparatusaccording to claim 6, wherein at least one bearing operates thepositioning device in one direction and at least one bearing operatesthe positioning device in another direction by means of differentcurrent pulses, said pulses being selected from the group of fixedfrequency pulses and variable frequency pulses.
 8. The apparatusaccording to claim 6, wherein the positioning device comprises athreaded shaft and a fastener for securing the shaft to the adjustabledevice.